Y. Aksenov

Parallel high-resolution confocal Raman SEM analysis of inorganic and organic bone matrix constituents

In many multi-disciplinary fields of science, such as tissue engineering, where material and biological sciences are combined, there is a need for a tool that combines ultrastructural and chemical data analysis in a non-destructive manner at high resolution. We show that a combination of confocal Raman spectroscopy (CRS) and scanning electron microscopy (SEM) can be used for such analysis. Studies of atomic composition can be done by X-ray microanalysis in SEM, but this is only possible for atomic numbers greater than five and does not reveal molecular identity. Raman spectroscopy, however, can provide information on molecular composition and identity by detection of wavelength shifts caused by molecular vibrations. In this study, CRS–SEM revealed that early in vitro-formed bone extracellular matrix (ECM) produced by rat osteoprogenitor cells resembles mature bone chemically. We gained insight into the structure and chemical composition of the ECM, which was composed of mainly mineralized collagen type I fibres and areas of dense carbonated calcium phosphate related to the collagen fibre density, as revealed by Raman imaging of SEM samples. We found that CRS–SEM allows the study of specimens in a non-destructive manner and provides high-resolution structural and chemical information about inorganic and organic constituents by parallel measurements on the same sample.

Integration of a confocal Raman microscope in an electron microscope

In this research project a confocal Raman micro spectrometer (CRM) will be designed and incorporated in a scanning electron microscope (SEM). The aim is to develop a new analytical instrumentation to investigate samples on their morphology, atomic composition and molecular composition. Application of the CRM-SEM is in the field of bio-material research where bio-compatibility with an d bio-degeneration by cells and tissues play an important role. The purposes of CRM is for using in medical, biological, chemical and other field science and technology. The energy of these vibration states depends on the molecular structure and environmental condition like PH, temperature. Therefore, the Raman spectrum contains information about the chemical composition of a substance and the structure of molecules. With CRM we can obtain a 3D image of molecular distribution in living cells or composite materials. In this way it provides directly and non-invasively, unique information about the spatial distribution of molecules in inhomogeneous systems. It is important information for such molecules as DNA, protein and other, where a lot of properties their molecules depends on configuration in space. Combining the capacities of the SEM and the CRM will add a powerful device for material investigation.